1. Field of the Invention
The present invention relates to simple mechanical analog computer devices, and more particularly to compact training and navigation aids for Automatic Direction Finder (ADF) and Very High Frequency Omni Range (VOR) navigation systems. It further involves visual and mechanical simulation of these primarily aircraft navigation systems for home study and for reference in actual flight.
2. Description of Prior Art
Previously known mechanical analog computer devices of the general type to which the present invention relates fall into two categories; namely, cards with two or more concentric rotating dials that show relative angles for ADF and pictures of VOR Meter readings for typical aircraft positions around a beacon, and devices which have two or more concentric dials comprising a dial assembly that is mounted to a support member, such that the dial assembly can be revolved or orbited around an axis representing the beacon center, without rotating about its own axis. Throughout this specification this movement is referred to as non-rotational orbiting.
A device of the latter type, which can show actual aircraft position and actual meter readings for totally unambiguous simulation is disclosed in U.S. Pat. No. 3,485,929, issued to William W. Tillery on Dec. 23, 1969. This device, however, is relatively bulky and expensive because of the use of gears and appropriate supports to mount the non-rotational orbiting dial assembly. Furthermore, gear backlash must be near zero to maintain required accuracy for unambiguous meter readings and this results in more cost and bulkiness. Additionally, that device pertains only to ADF simulation or its derivatives, not to ADF and/or VOR simulation. Whereas ADF is commonly used as a back-up, VOR is the primary system used for most current aerial navigation.